The ergative case marks the agent of a transitive verb. The ergative suffix is -le/-re/-lle/-?ille. The form of the ergative suffix is /-le/ for the indefinite and /-?ille/ for the definite after the consonants /?/, /k/, /t/, /p/, /b/, /ŋ/, /n/ and /m/.

To illustrate what is meant by an ‘Ergativeʼ structure, consider the following set of examples:
(155) (a) John broke the door(155) (b) The door broke
(156) (a) John might drown the kittens(156) (b) The kittens might drown
(157) (a) The artillery will sink the ship(157) (b) The ship will sink
(158) (a) John rolled the ball down the hill(158) (b) The ball rolled down the hill
Following the terminology adopted in Chapter 7 (after Burzio (1986), p. 30), we might say that the (a) member of each of these pairs is a transitive structure, and the (b) member an ergative structure. In Burzioʼs use of the term, an ergative Clause is an intransitive Clause which has a transitive counterpart in which the transitive Object corresponds to the ergative Subject.

In Kurdish, on the other hand, the corresponding compound construction, which appears to have been the model for the NENA[North-Eastern Neo-Aramaic] construction, is ergative in form when the verb is transitive.

Woodbury (1975) does argue, however, that absolutives are more relativisable in Greenlandic than are ergatives, on the grounds that (1) RCs[Relative Clauses] formed on ergatives are somewhat more restricted in the distribution in matrix clauses (p. 21) than are those formed on absolutives, and (2) for certain verb classes ergatives cannot be relativised out of the active participle (p. 27).

Ergatives share close similarities with agentless passives: Both are intransitive, both lack an agent, while the patient appears in the subject position. As the acquisition data show, learners seem to treat ergatives like passives.